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CRITICAL.POINT (CP)
CRITICAL.POINT (CP)
The CRITICAL.POINT; command is used in Reports to enable easy and rapid recovery
following a system failure.
Restrictions on CRITICAL.POINT; commands
For an MCP based LINC System, CRITICAL.POINT; commands are not allowed with
Reports being output to Video.
There is a maximum limit of 99 Critical Points in one Report.
The CRITICAL.POINT; command can be inserted anywhere in main Report logic, except
within DETERMINE or LOOK.UP loops. It may be necessary to include logic to exit such
loops before performing a Critical Point.
What Happens at a Critical Point
During normal operation, the following processes occur at a Critical Point:
$ Recovery data is moved from memory to the LINC database.
$ In Direct Reports printed under the LINC Report Output Control System (ROC), all
print files are released, and completed parts of Direct Reports are printed. For a UNIX
LINC System, if output is being directed to a file, this means that a new output file is
created for each release. For LDA, all print files are released and all disk files (such as
extract files) are closed. The release of print files can be inhibited by including the
NO.RELEASE; command option.
$ Profile information is reset. This means that after the Critical.Point, data must be
retrieved from the LINC Database before FLAG; commands can be used successfully.
Automatic Entries will function correctly without additional retrieval.
Ensure that reference data items are brought into memory by DETERMINE; or
LOOK.UP; commands before executing the CRITICAL.POINT; command.
$ For UNIX and MCP based LINC Systems, an end-of-transaction is forced. (For an MCP
based LINC System, in a LINC Report (including a LINC Report generated as a
Coroutine), the CRITICAL.POINT; command performs an end transaction and then
waits for any specified sleep time. See the CALL; command for details of Coroutines.)
$ On OS 2200 based LINC Systems, a COMMIT of database updates occurs.
$ For performance reasons, ensure that the number of Critical Points used is not
excessive.
$ Extract files that were open for output are CLOSED.
On Recovery
When recovery takes place after a system failure, the Critical Point performs an automatic
read of recovery data back into memory and resumes processing at the instruction
immediately following the most recently processed CRITICAL.POINT; command.
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